1. Field of the Invention
The present invention relates to a driving apparatus of a multi-function machine having a printer function and a scanner function, and more particularly to a power transmitting apparatus, which is able to prevent two coupled power transmitting gears from being disengaged from each other or worn away by each other when two frames, having the two coupled power transmitting gears mounted thereon, are wrongly assembled, where the power switching apparatus is able to drive a plurality of driving systems by one driving source, and a driving apparatus of a multi-function machine using the same.
2. Description of the Related Art
FIG. 1 shows a general multi-function machine 1. The multi-function machine 1 has a scanner unit 10 to scan data recorded on a sheet of document, and a printer unit 40 to print the data on the sheet of paper for an output, as basic components. According to a design, the multi-function machine 1 further includes a facsimile unit to copy the data and to transmit or receive the data through communication lines.
As shown in FIG. 2 and FIG. 3, the scanner unit 10 includes a document transport part 8 to transport the sheet of document D, a scanner 18 to read data out of the sheet of document D delivered from the document transport part 8, and a scanner driving part 20 to drive the scanner 18.
The document transport part 8 is provided with a document tray 14 to load the sheet of document D, a document sensor 15 to detect whether the sheet of document D is loaded in the document tray 14, a document pickup roller 13 to pick up the sheet of document D according to the operation of the document sensor 15, a friction pad 9 to be in contact with the document pickup roller 13 with a predetermined pressure to separate the sheet of document D sheet by sheet. A white roller 17 is provided to transport the picked-up sheet of document D while bringing the picked-up sheet of the document D to be in contact with the scanner 18, and a document discharge roller 19 is provided to discharge the sheets of document D past through the scanner 18 and the white roller 17 out of the machine 1.
The scanner 18 includes a contact image sensor (CIS) (not shown) mounted on a scanner frame 3 to read data out of the sheet of document D.
The scanner driving part 20, which is disposed on the scanner frame 3, includes a scanner driving motor 21, a scanner driving gear 22 formed on the scanner driving motor 21, and a plurality of engaging gears 23, 25, 26, 27, 29, 30, and 32 and a first reduction gear 24 to transmit a rotational force of the scanner driving gear 21 to a document pickup roller gear 28, a white roller gear 31, and a document discharge roller gear 33.
As shown in FIGS. 1, 2 and 4, the printer unit 40 includes a carrier 41 having a print head 43 with an ink jet nozzle mounted thereon, a carrier frame 12 to support a guide rail 11 and a carrier shaft 49 guiding the movement of the carrier 41, a carrier driving part 50 to move the carrier 41 right and left along the carrier shaft 49, a paper transport part 42 to transport a sheet of paper P loaded in a paper cassette 48 and a printer driving part 60 to drive the paper transport part 42.
The carrier 41 is provided with a guide slider 56 formed at a rear and an upper side thereof to be movable right and left along the guide rail 11, and a support bracket 47 supported on the carrier shaft 49 to be movable right and left therealong.
As shown in FIGS. 1 and 2, the carrier driving part 50 includes a carrier driving motor 51 fixed on the carrier frame 12 below the guide rail 11, and a carrier driving belt 53 connected with a carrier driving gear 52 of the carrier driving motor 51 to transmit a power of the carrier driving motor 51 to a power transmitting teeth portion 54 of the support bracket 47 formed at a rear side of the carrier 41, thereby moving the carrier 41 right and left.
The paper transport part 42 includes a paper pickup roller 44 to pick up the sheet of paper P to be printed, a paper transport roller 45 to transport the sheet of paper P picked-up by the paper pickup roller 44, and a paper discharge roller 46 to discharge the sheet of paper P.
The printer driving part 60 includes paper feed driving motor 61 fixed on a lower side of a paper feed frame 5 (FIG. 1), a paper-feed driving gear 62 formed at the paper-feed driving motor 61, and a plurality of engaging gears 63, 65, 66, 67, 69, 70, 71 and 75 and second reduction gears 64, 68 and 73 to transmit the rotation force of the driving motor gear 62 to a paper pickup roller gear 72, paper transport roller gear 74, and a paper discharge roller gear 76.
In operation of the multi-function machine 1 constructed above, during a scanning mode for copying or transmitting the data recorded on the sheet of document P, the scanner driving motor 21 drives the scanner driving part 20 to operate the scanner unit 10, and during a printing mode for printing, the paper-feed driving motor 61 and the carrier driving motor 51 drive, respectively, the printer driving part 60 and the carrier driving part 50 to operate the printer unit 40.
However, such a conventional multi-function machine 1 has an advantage that because the scanner driving part 20 and the printer driving part 60 disposed to have a same power transmitting direction are respectively driven by separate motors 21 and 51, a structure and a method to drive the scanner unit 10 and the printer unit 40 to carry out the scanning and printing operations can be easily embodied. However, a problem exists in the conventional multi-function machine 1 in that a fabrication cost increases owing to a use of two high-priced driving motors.
Also, in the conventional multi-function machine 1, because the scanner driving part 20 or the printer driving part 60 uses the gears 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, and 33, or the gears 62, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73, 75, and 76, there are frequent occasions when a portion of the gears 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, and 33, or 62, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73, 75, and 76 should be mounted on a different support frame instead of the scanner frame 3 or the paper feed frame 5.
In this case, during assembling, the scanner frame 3 or the paper feed frame 5 is apt to be wrongly assembled with the other support frame by the fabrication tolerance.
Thus, when the frames are wrongly assembled with each other, a distance between the frames is varied, so that an engagement between coupled gears mounted on respective frames can become loose, thereby resulting in a problem that the coupled gears are disassembled from each other or worn away by each other during power-transmitting, and a power transmitting performance therebetween is deteriorated.